Alyssa Cole writes in multiple genres, including the Edgar Award–winning thriller When No One Is Watching and the Reading List Award–winning historical romance An Extraordinary Union. Her newest, One of Us Knows (Morrow), features a protagonist with dissociative identity disorder (DID) whose system of personalities work together to solve a locked-room case on a mysterious island. Cole talks with LJ about writing, research, and books she enjoys.

What would you like readers to know about your new book?

One of Us Knows is a twisty northern gothic thriller in which a dissociative identity system find themselves caretaker of an island castle on the Hudson. It’s the most ambitious and difficult thing I’ve ever written! Dual locked-room mysteries. Multiple character POVs from people who all share the same body but not the same access to information. Romantic entanglements. Missing people and murders. Links between the far past, the recent past, and the present, from politics and mental health to patriarchy. I definitely challenged myself with this book.

The character with DID is Ken. What prompted you to incorporate this into the plot, and what was the biggest challenge for you as a writer when it came to bringing Ken to life?

I really wanted to write a story where the existence of a DID system isn’t a twist-surprise at the climax of the story but an important aspect of character and plot from the first page. Bad Day system is [a team of] detectives who need to work together in order to survive, which fits the genre perfectly.

The biggest challenge was figuring out each member of Bad Day system, who they were as a person and as a part of the group and where they fit into the unraveling mysteries. Also, as someone who doesn’t have DID, I wanted to write a portrayal that was accurate and, most importantly, not harmful to that community. This wasn’t exactly a challenge, since it’s a normal part of the writing process for me, but it did require a lot of research, consultation, and reflection on mental health.

You mention your research process. Can you talk more about how you explored this community?

I read books and memoirs from both people with DID and psychiatrists who had treated them, as well as research papers, blog posts, and whatever I could find. I watched videos and listened to podcasts. I also spoke with my accuracy consultant, who gave me amazing feedback. I already basically knew what I wanted to happen in the story, and my research goal was to make sure that what I was writing was within the realm of possibility and not unintentionally harmful…. Realistically, no amount of research will make a book absolutely authentic, but I’ve always written characters who are different from myself, and I think it’s one of my strong points as a writer.

As with When No One Is Watching, One of Us Knows is called a social thriller. Why is it important for you to address issues of injustice in society in your novels?

I’ve always been fascinated with human nature: the best aspects of it and the worst, the highs of love and the lows of atrocity. There’s an inclination to avoid deeply understanding the latter, to look away from the things that are so immense and unjust that we can’t fully take them in without some level of distress or trauma. Generally, we are encouraged to look away because once someone is aware of injustice, they, on some level, start paying attention to their moral compass. Like many writers and other artists, I am the kind of person who can’t quite look away. My books are a way of transmuting heavy topics that are important to me into stories that can, hopefully, entertain.

Many of your books also have a historical component. What is it about the past that fascinates and inspires you as a writer?

There’s a famous Faulkner quote: “The past is never dead. It’s not even past.” I tend to pick up on historical patterns, links between the past and present that are often the result of the way we, as a society, try to move forward without ever fully putting an end to the mistakes of the past. I guess a different way of putting it is, we aren’t doomed to repeat history, we are history. I like showing how we are intimately connected to things that “happened a long time ago.”

Is Kavanaugh Island based on a real place?

Yes! It’s loosely based on Bannerman’s Island (Pollepel Island) near Beacon, NY. I saw it through a train window years and years ago, and I guess the seed of an idea hung around, waiting for the right story to germinate it.

What are some of your own favorite crime fiction novels?

The “Detective Elouise Norton” series by Rachel Howzell Hall; Missing White Woman by Kellye Garrett; The Decagon House Murders by Yukito Ayatsuji; The Guest List by Lucy Foley; My Sister, the Serial Killer by Oyinkan Braithwaite; Not So Perfect Strangers by L.S. Stratton; The Inugami Curse by Seishi Yokomizo.